FIG. 1.

MDBK cells infected with recombinant BoHV-1 (MOI, 0.5) expressing the GFP-VP26 fusion protein. (A) Cells after 42 h of incubation, fixation, and DAPI staining. The intense signals in cells 1 and 2 correspond to the accumulation of capsids and/or virions embedded in protein within the nucleus and cytoplasm (1) or only within the nucleus (2). Nuclear fragments and membranes, despite lost integrity, were recognized by CTEM. (B) Micrograph obtained by CTEM from cell 3 with only a faint fluorescence signal. The nucleus bears single capsids (arrows), capsids in small clusters, and membranous inclusions. Chromatin is condensed at the periphery, indicating apoptosis, and the nuclear membrane is intact. (C) Deconvolution of the nucleus after fixation and DAPI staining of a noninfected cell. The disk-like nucleus has diameters of 18.5, 15, and 2.5 μm and a calculated surface of 133 μm². (D) Deconvolution of a nucleus after fixation and DAPI staining of an infected cell incubated for 42 h. The disk-like irregularly shaped nucleus with the short diameter of about 3.5 μm contains irregularly distributed chromatin and accumulation of capsids. The surface is calculated to be approximately 160 μm². Bars, 10 μm (A); 1 μm (B to D).